scholarly journals Obstacle Avoidance of Two-Wheel Differential Robots Considering the Uncertainty of Robot Motion on the Basis of Encoder Odometry Information

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 289 ◽  
Author(s):  
Jiyong Jin ◽  
Woojin Chung
Keyword(s):  
Obstacle Avoidance ◽  
Experimental Results ◽  
Robot Motion ◽  
Control Performance ◽  
Velocity Control ◽  
Uncertainty Sources ◽  
Control Scheme ◽  
Collision Safety ◽  
Different Types ◽  
Simulation Results

It is important to overcome different types of uncertainties for the safe and reliable navigation of mobile robots. Uncertainty sources can be categorized into recognition, motion, and environmental sources. Although several challenges of recognition uncertainty have been addressed, little attention has been paid to motion uncertainty. This study shows how the uncertainties of robot motions can be quantitatively modeled through experiments. Although the practical motion uncertainties are affected by various factors, this research focuses on the velocity control performance of wheels obtained by encoder sensors. Experimental results show that the velocity control errors of practical robots are not negligible. This paper proposes a new motion control scheme toward reliable obstacle avoidance by reflecting the experimental motion uncertainties. The presented experimental results clearly show that the consideration of the motion uncertainty is essential for successful collision avoidance. The presented simulation results show that a robot cannot move through narrow passages owing to a risk of collision when the uncertainty of motion is high. This research shows that the proposed method accurately reflects the motion uncertainty and balances the collision safety with the navigation efficiency of the robot.

scholarly journals Super-Twisting Algorithm Applied to Velocity Control of DC Motor without Mechanical Sensors Dependence

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6041
Author(s):  
Fredy A. Valenzuela ◽  
Reymundo Ramírez ◽  
Fermín Martínez ◽  
Onofre A. Morfín ◽  
Carlos E. Castañeda
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Dc Motor ◽  
Experimental Results ◽  
Resistive Load ◽  
Velocity Control ◽  
Velocity Sensor ◽  
Control Scheme ◽  
Mechanical Sensors ◽  
Twisting Algorithm

A DC motor velocity control in feedback systems usually requires a velocity sensor, which increases the controller cost. Additionally, the velocity sensor used in industrial applications presents several disadvantages such as maintenance requirements and signal conditioning. In this work, we propose a robust velocity control scheme applied to a DC motor based on estimation strategies using a sliding-mode observer. This means that measurements with mechanical sensors are not required in the controller design. The proposed observer estimates the rotational velocity and load torque of the motor. The controller design applies the exact-linearization technique combined with the super-twisting algorithm to achieve robust performance in the closed-loop system. The controller validation was carried out by experimental tests using a workbench, which is composed of a control and data acquisition Digital Signal Proccessor board, a DC-DC electronic converter, an interface board for signals conditioning, and a DC electric generator connected to an adjustable resistive load. The simulation and experimental results show a significant performance of the proposed control scheme. During tests, the accuracy, robustness, and speed response on the controller were evaluated and the experimental results were compared with a classic proportional-integral controller, which uses a conventional encoder.

VEHICLE CONTROL OF VEHICLES SEPARATING FROM VEHICLE PLATOON

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Eisuke Kita ◽  
Ryoma Sato ◽  
Miichiro Yamada ◽  
Tatsuhiro Tamaki
Keyword(s):  
Objective Function ◽  
Traffic Flow ◽  
Computational Simulation ◽  
Vehicle Control ◽  
Control Model ◽  
Experimental Results ◽  
Velocity Control ◽  
Vehicle Platoon ◽  
Simulation Results ◽  
The Difference

Vehicle platoon is very important techniques for increasing the traffic flow safely and effectively. The electric and mechanical systems are necessary for effective vehicle platoon. Several systems have been studied for control vehicles in the platoon. This paper focuses on the velocity control of the vehicles separating from the vehicle platoon. The velocity control model is defined according to the vehicle following model and then, the parameters are determined by minimizing the objective function. The model with the optimized parameters is applied for the vehicle platoon experiment of LEGO Mindstorms NXT. The experimental results are compared with the simulation results in order to confirm the validity of the model. Although the experimental results finally converge to the simulation results, there exists the difference between the computational simulation and the experimental results because of the error of the sensor and the others.

Robust Backstepping Control for Longitudinal Flight Dynamics

2013 ◽  
Vol 300-301 ◽  
pp. 1589-1592
Author(s):  
Ming Suo Li ◽  
Mou Chen ◽  
Rong Mei
Keyword(s):  
Flight Control ◽  
Sliding Mode ◽  
External Disturbance ◽  
Flight Dynamics ◽  
Backstepping Technique ◽  
Control Performance ◽  
Sliding Mode Disturbance Observer ◽  
Control Scheme ◽  
Simulation Results ◽  
Robust Flight Control

In this paper, the robust longitudinal flight control is developed for the fighter using the backstepping technique. To improve the robust control performance for the unknown external disturbance, the sliding mode disturbance observer is employed to estimate the unknown external disturbance. Utilizing the disturbance estimate output, the robust backstepping flight control scheme is proposed for the fighter with the unknown external disturbance. Finally, simulation results are given to show the effectiveness of the proposed robust flight control scheme for longitudinal flight dynamics.

scholarly journals Which Parameters Control the Leg Movement of a Walking Insect?: I. Velocity Control during the Stance Phase

1985 ◽  
Vol 116 (1) ◽  
pp. 343-355 ◽  
Author(s):  
H. CRUSE
Keyword(s):  
Stance Phase ◽  
Stick Insect ◽  
Experimental Results ◽  
Velocity Control ◽  
Carausius Morosus ◽  
Different Types ◽  
Leg Movement ◽  
Position Servo

In treadwheel walking, the front and middle legs of the stick insect (Carausius morosus) propel the wheel, while the hind legs exert very little force and can even decelerate the wheel. This result is compared with observations on the function of the legs in different walking situations. Several hypotheses assuming different types of position servo-mechanisms have been proposed in the literature on the control of leg movement during walking in insects. The experimental results support none of these hypotheses. Instead, they indicate that velocity rather than position is the variable controlled during the stance phase.

scholarly journals NAO robot obstacle avoidance based on fuzzy Q-learning

2019 ◽  
Vol 47 (6) ◽  
pp. 801-811 ◽  
Author(s):  
Shuhuan Wen ◽  
Xueheng Hu ◽  
Zhen Li ◽  
Hak Keung Lam ◽  
Fuchun Sun ◽  
...  
Keyword(s):  
Obstacle Avoidance ◽  
Autonomous Navigation ◽  
Learning Algorithm ◽  
Experimental Results ◽  
Content Type ◽  
Q Learning ◽  
Nao Robot ◽  
Learning Speed ◽  
Simulation Results ◽  
Fractional Controller

Purpose This paper aims to propose a novel active SLAM framework to realize avoid obstacles and finish the autonomous navigation in indoor environment. Design/methodology/approach The improved fuzzy optimized Q-Learning (FOQL) algorithm is used to solve the avoidance obstacles problem of the robot in the environment. To reduce the motion deviation of the robot, fractional controller is designed. The localization of the robot is based on FastSLAM algorithm. Findings Simulation results of avoiding obstacles using traditional Q-learning algorithm, optimized Q-learning algorithm and FOQL algorithm are compared. The simulation results show that the improved FOQL algorithm has a faster learning speed than other two algorithms. To verify the simulation result, the FOQL algorithm is implemented on a NAO robot and the experimental results demonstrate that the improved fuzzy optimized Q-Learning obstacle avoidance algorithm is feasible and effective. Originality/value The improved fuzzy optimized Q-Learning (FOQL) algorithm is used to solve the avoidance obstacles problem of the robot in the environment. To reduce the motion deviation of the robot, fractional controller is designed. To verify the simulation result, the FOQL algorithm is implemented on a NAO robot and the experimental results demonstrate that the improved fuzzy optimized Q-Learning obstacle avoidance algorithm is feasible and effective.

PDF Subvariable Control and Its Application to Robot Motion Control

1989 ◽  
Vol 111 (3) ◽  
pp. 452-461 ◽  
Author(s):  
M. C. Leu ◽  
D. I. Freed
Keyword(s):  
Feedback Control ◽  
Nonlinear System ◽  
Motion Control ◽  
Response Speed ◽  
Experimental Results ◽  
Robot Motion ◽  
Velocity Feedback ◽  
Control Scheme ◽  
Control Schemes ◽  
Manipulator Arm

A method for determining the feedback coefficients of pseudo-derivative-feedback control is presented, along with applications of this control scheme. Simulations are performed for controlling a linear inertia system with disturbance loads and inertia variations, and for controlling a nonlinear system represented by a manipulator arm. The results show that PDF subvariable control quickly rejects disturbances and is insensitive to inertia variations. Also, the position responses do not exhibit overshoot or oscillation. Comparison with the results for proportional-plus-velocity-feedback control shows that the PDF approach is superior in response speed, robustness, and disturbance-handling ability. Experimental results from implementation of both control schemes to a revolute manipulator support this conclusion.

scholarly journals Sliding mode control for quadrotor with disturbance observer

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878233 ◽  
Author(s):  
Nigar Ahmed ◽  
Mou Chen
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Unstable State ◽  
Control Performance ◽  
Mode Control ◽  
Exogenous Disturbance ◽  
Control Scheme ◽  
Simulation Results ◽  
Unknown Disturbance

In this article, a sliding mode control scheme is proposed for a quadrotor in the presence of an exogenous disturbance. A nonlinear sliding mode surface is constructed based on the estimate output of a disturbance observer to reject the effect of the unknown disturbance in the quadrotor. The desired control performance is achieved by bringing the state from unstable state to stable ones. To show the effectiveness of the developed control scheme, simulation results are provided for illustration of the designed controller based on disturbance observer.

The Research of Robot Teleoperation Technology Based on Virtual Fixture

2014 ◽  
Vol 571-572 ◽  
pp. 1097-1101
Author(s):  
Shi Kun Xu ◽  
Xin Gao ◽  
Tao Zhang ◽  
Han Xu Sun ◽  
Qing Xuan Jia
Keyword(s):  
Obstacle Avoidance ◽  
Trajectory Tracking ◽  
Experimental Results ◽  
Operational Performance ◽  
Control Performance ◽  
Teleoperation System ◽  
Virtual Fixture ◽  
Tracking Motion ◽  
And Control

In robot teleoperation, safety and operational performance are two important indicators. This paper presents a way to use virtual fixture to assist robot teleoperation and studies the realization method of virtual fixture assisting teleoperation in trajectory tracking, motion navigation and obstacle avoidance. The simulation experimental results indicate that virtual fixture method improves security and control performance of teleoperation system.

Generating Situation-Dependent Behavior: Decentralized Control of Multi-Functional Intestine-Like Robot that can Transport and Mix Contents

2013 ◽  
Vol 25 (5) ◽  
pp. 871-876 ◽  
Author(s):  
Takeshi Kano ◽  
◽  
Toshihiro Kawakatsu ◽  
Akio Ishiguro ◽  
◽  
...  
Keyword(s):  
Decentralized Control ◽  
Coupled Oscillators ◽  
Sensory Feedback ◽  
Specific Task ◽  
Physical Conditions ◽  
Dependent Behavior ◽  
Intestinal Movement ◽  
Control Scheme ◽  
Different Types ◽  
Simulation Results

Most robots are designed to perform a specific task in a predefined environment and have difficulty in producing situation-dependent behavior. To tackle this problem, we focus here on a mammal intestine that either transports or mixes the contents depending on the encountered circumstances. We propose a simple model for the intestinal movement and design an autonomous decentralized control scheme for an intestine-like robot by using coupled oscillators with local sensory feedback. Simulation results show that different types of motions are generated depending on the the physical conditions of the intestine and its contents. Our simulated robot does not require any input from a higher center to switch between different types of motions but determines autonomously which motion to generate. This study thus paves the way for developing “multi-functional robots” whose behavior is changed flexibly and spontaneously depending on circumstances.

Shaking Functionality Evaluation of Four Different Types of Citrus Canopy-Shaker Tines

2018 ◽  
Vol 34 (5) ◽  
pp. 809-817 ◽  
Author(s):  
Tian-Hu Liu ◽  
Reza Ehsani ◽  
Arash Toudeshki ◽  
Muna Abbas ◽  
Xiang-Jun Zou
Keyword(s):  
Field Trials ◽  
Experimental Results ◽  
Vibrational Response ◽  
High Stiffness ◽  
Different Types ◽  
Simulation And Experiment ◽  
Simulation Results ◽  
Positive Effect ◽  
Tree Injuries ◽  
Canopy Shaker

Abstract. The shaking functionality of different types of shaking tines for citrus canopy shakers was evaluated. Shaking responses were simulated using ANSYS/LS-DYNA, and a tractor-mounted experimental shaking machine developed for conducting field trials. Straight nylon, bent nylon, straight PVC, and straight steel tines were used as shaking rods and, in experiments, accelerometers placed at branches and fruit to detect vibrational acceleration. Simulation results indicated that tine materials affected the vibrational response of trees and the acceleration peaks of branches and limbs exerted by a steel tine were ~2.0 times as high as exerted by a nylon tine. Both simulation and experimental results demonstrated that the tine bending stiffness had a positive effect on the generated acceleration. Tree injuries caused by a straight nylon tine were much less than by other tines. The results suggested that a shaking tine should have high stiffness, but its surface should be soft. These simulation and experiment methods can be used for improving canopy shaker applications. Keywords: Citrus harvest, Canopy shaking, Shaking functionality, Trial.

Sign in / Sign up

Export Citation Format

Share Document